Certain environmentally persistent chlorinated hydrocarbons, in particular polychlorinated biphenyls and bis(4-chlorophenyl)-1,1,1- trichloroethane (DDT)-derived compounds have been associated in recent epidemiological studies with an increased incidence of breast cancer among women in the US. The known estrogenic and anti-estrogenic properties of these compounds have been hypothesized to be involved in the etiologic pathway of breast carcinogenesis. However, laboratory- based studies of possible underlying molecular mechanisms in normal human mammary epithelial cells have been few. To study mechanisms by which chlorinated hydrocarbons may be involved in the etiology of cancer of the female breast, this project will evaluate the ability of these compounds to alter carcinogen metabolism in normal human mammary epithelial cells. Mammary epithelial cells from healthy women are available as discard tissues following reduction mammoplasty in our institute. These tissues will be used in this study. The cellular material will be released by coarse dissection and enzymic digestion. The cells will be propagated for 8 - 10 passages to obtain enough cells for an entire experiment. The cells will be incubated with either: 1) Aroclor 1254, a commercial polychlorinated biphenyl mixture or 2) a non-polar sediment extract from New York City waterways (from Project 5) containing polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and branched alkanes. Then the metabolism, activation and formation of DNA-adducts of one of three radiolabeled carcinogens or potential carcinogens: benzo[a]pyrene, benzene or 17beta-estradiol in these normal human mammary epithelial cells will be studied. Carcinogen- DNA adducts will be isolated by enzymic digestion and high performance liquid chromatography. Adduct identification will be made by co- chromatography with available standards. Levels of adducts will be determined by liquid scintillation counting. In the event that an unknown adduct is detected, large-scale cultures from individuals with a high propensity for metabolic activation will be used to prepare materials for analysis by mass spectrometry. Metabolites present in the media will be analyzed similarly. By these means, interindividual and inter-racial (African-American, Latino and Caucasian) variations in metabolic inducibility and carcinogen metabolism in normal human mammary epithelial cells will be determined. This project, in concert with other components of this Program, will elucidate the role of environmental chlorinated hydrocarbons in the etiology of female breast cancer.